Mercurial > hg
view hgweb.cgi @ 36701:d77c3b023393
lock: block signal interrupt while making a lock file
On Windows where symlink isn't supported, util.makelock() could leave an empty
file if interrupted immediately after os.open(). This empty lock never dies
as it has no process id recorded.
ld = os.open(pathname, os.O_CREAT | os.O_WRONLY | os.O_EXCL)
# an interrupt may occur here
os.write(ld, info)
os.close(ld)
This was a long-standing bug of TortoiseHg which runs a command-server and
kills it by CTRL_C_EVENT, reported by random Windows users.
https://bitbucket.org/tortoisehg/thg/issues/4873/#comment-43591129
At first, I tried to fix makelock() to clean up a stale lock file, which
turned out to be hard because any instructions may be interrupted by a
signal.
ld = None
try:
# CALL_FUNCTION # os.open(...)
# an interrupt may occur here
# STORE_FAST # ld = ...
ld = os.open(pathname, os.O_CREAT | os.O_WRONLY | os.O_EXCL)
os.write(ld, info)
...
return True
except:
if ld:
...
os.unlink(pathname)
return False
So I decided to block signals by temporarily replacing the signal handlers
so makelcok() and held = 1 will never be interrupted.
Many thanks to Fernando Najera for investigating the issue.
author | Yuya Nishihara <yuya@tcha.org> |
---|---|
date | Sat, 03 Mar 2018 23:49:39 -0500 |
parents | 4b0fc75f9403 |
children | 47ef023d0165 |
line wrap: on
line source
#!/usr/bin/env python # # An example hgweb CGI script, edit as necessary # See also https://mercurial-scm.org/wiki/PublishingRepositories # Path to repo or hgweb config to serve (see 'hg help hgweb') config = "/path/to/repo/or/config" # Uncomment and adjust if Mercurial is not installed system-wide # (consult "installed modules" path from 'hg debuginstall'): #import sys; sys.path.insert(0, "/path/to/python/lib") # Uncomment to send python tracebacks to the browser if an error occurs: #import cgitb; cgitb.enable() from mercurial import demandimport; demandimport.enable() from mercurial.hgweb import hgweb, wsgicgi application = hgweb(config) wsgicgi.launch(application)